Grinding device.



C. H. DAVIS.

GRINDING DEVICE.

APPLICATION. FILED JULYH, 1911.

1 ,2l@,@52 Patented Dec. 26, 1916.

kfnesse I fi- 7 m.

eamnme DEVICE.

specification of Letters Patent.

Patented Dec. as, rare.

Application ma e m 11, m1. Serial no. csaoae.

To all whom it may concern:

Be it known. that I, CHARLES'H. Davis, a citizen of the United States, residin at Worcester, in the county of Worcester, tate of Massachusetts, have invented a certain new and useful Improvement in Grinding Devices, of which the following'is a specification, reference being had therein to the accompanying. drawings.

This invention relates to grinding devices, but more particularly to such as are adapted for use in connection with dentistry.

Heretofore the abrasive disks have been secured to the fiat extremity of a mandrel by means of a screw which is passed through a central orifice in the disk and enters a threaded hole in the mandrel; but this device could only be operated in one direction, as a revolution in the other direction caused the disk to unscrew the binding screw and thus release the former. Furthermore in this construction it was necessary to bind the disk tightly against the end of the mandrel to permit it to be used and thus the disk could only rotate in a plane perpendicular to the am's of the mandrel. This rigidity of the grinding device caused great diflioulty in operating on the surfaces of teeth at points where the mandrel could not be held in a position perpendicular to the surface to be ground, and frequently such a device caused the teeth to be notched.

The object of the present invention is to provide a grinding device which may be operated in either direction and which is very flexible.

The many features and advantages of the invention will be hereinafter fully described and included in the claims.

Referring to the drawings, Figure 1, is a side elevation of the invention complete. Fig. 2, side elevation of a modification of the invention as will be described more fully hereinafter. Fig. 3, detail view of the parts of the invention. Fig. 4, rear view of the grinding disk. Fig. 5, end view of mandrel, as will be fully described hereinafter. Figs. 6-8, detail views of grinding disks and parts thereof. Fig. 9, same as Fig. 1 but with-binding screw partially withdrawn to illustrate the operation of the disk at an angle to the axis of the mandrel.

In the drawings the invention is shown to consist of a mandrel 10 provided with a central threadedmrifice 11 in which enters the threaded binding screw 12 provided with a head 13. This screw 13 is adapted to secure to the extremity of the mandrel 10 a grinding member 14 which is provided with a central orifice 15 to permit the passage therethrough of the screw 12. The extremity of the mandrel which contacts withthe grinding member 14, is provided with a plurality of fingers 16 which are adapted to enter sockets 17 in the. rear face of the grinding member 14.

Two forms of the grinding member have been illustrated in Figs. 68, inclusive, the one shown-in Fig. 6 having an inserted hub with the indentations 17 in this hub, and the other form having the hub integral with the grinding member, as is shown in Figs.

.of these fingers may be varied at will,

though it is undesirable to have less than four if it is intended to use the device in the method illustrated in Fig. 9; as there might be times when no fingers would lie within the sockets and the grinding member would thus be liable to slip, causing an uneven operation. It has been found advisable to construct the fingers tapering on their inner and side faces to permit them to readily enter the corresponding sockets, and to also more firmly position the grinding member relative to the axis of the mandrel.

In the ordinary form of device of this type, wherethe extremity of the mandrel contacting with the disk or grinding member is flat, it has been found that after a short period of use the orifice through the disk becomes enlarged, and thus the device depends upon the friction of the extremity of the mandrel, to-not only rotate the disk, butalso to prevent the latter from transverse movement. In the present device, the orifice in the disk or grinding member need not fit the screw as the device does not depend upon this screw to center the disk, for this function is eficiently. performed bythe fingers on the mandrel. Furthermore, it is necessary that the similar in construction to that shown in the other figures, but a cup-shaped cleaning member 19 is held against the end of the mandrel instead ofthe abrasive disk disclosed in the other figures. As this'cleaning member 19 is; usually constructed ofsoft rubber, .it has not been found necessary to provlde the same with sockets such as are used in rigid grindin members, for the advancing of the bin ing screw forces the cleaning member against the fingers on the mandrel, and thus these fingers form their own seats orv sockets in the member.

The inserted hub 20 in the grindingdisk, one form of which is disclosed in Figs. 4 and 6, may be constructed of lead or any other suitable material, and may be cement ed or otherwise secured therein or theretol Throughout the foregoing description, the

device has been described as applied to den- 4 gagement.

tal instruments, but it should be clearly understood that the invention involved therein may be equally applied to any construction in which a wheel, disk or other form of member is to be secured upon a rotatable driving shaft.

What I claimas my invention and desire to secure by Letters Patent is 1. In a device of the class'deseribed, the combination of a driving shaft and a driven wheel carried thereby, with a plurality of projections on one of these members adapted to engage the other member, and means for.

resiliently retaining said members in en,

2. In a device of the class described, the combination of a driving shaft and a driven wheel carried thereby, with a plurality of fingers about the axis of one of these members adapted to enter corresponding sockets in the other member, and means for. resiliently retaining said members in engagement.

3. In a device of the class described, the

' combination of a driving shaft, a driven disk mounted thereon and free to rockrelative thereto, a plurality of fingers on one of these members adapted ,to enter corresponding sockets in the other member, andmeans for retaining said-fingers within said sockets.

. .4. In a device'of the class described, the combination of a mandrel provided at one extremity with a plurality of projections, a threaded hole in said extremity concentric with said mandrel, a wheel provided with a central orifice therethrough, a headed screw adapted to pass through said orifice and have a portion thereof fit within said threaded hole, and-sockets in said wheel to receive theopposing projections on said mandrel. y

5. In a device of the class described, the

combination ofa mandrel provided at one extremity with a. plurality of tapering fingers projecting longitudinally therefrom and concentric therewith, a threaded hole in said'extremity concentric with said mandrel, an abrasive disk provided with .an inserted hub'having a central orifice therethrough, a binding screw adapted to pass through said orifice and have a portion thereof fitwithin said threaded hole, and a plurality of sockets in said hub adapted to receive the opposing fingerson said mandrel and to held in coactive relation therewith by said binding screw.

6. In a device of the class described, the

combination of ,a mandrel provided at one extremity with a plurality of projections, a

threaded hole in said extremity concentrlc with said mandrel, a disk provided with a central orifice therethrough, a binding screw adapted to pass through said orifice and have a portion thereof fitwithin .said threaded hole, sockets in said disk adapted to receive the opposing projections on said mandrel,

and resilient means on said screw adapted to act between the head thereof and the opposing face of said wheel or disk.

In testimony whereof I aflix my. signature, in' presence of two witnesses.

Witnesses:

f HABTLEY W. Bamnnrr,

' H. M. KENNEDY.

CHARLES H. DAVIS. 

